Thomas a



nurse STATES THOMAS A. EDISON, or MENLO PARK, NEW JERSEY, lissienosuoTHE EDISON ELEQTRIO LIGHT COMPANY, OF NEW YORK, N. Y.

INCANDESCENT co'unucros res ELECTR-HC LAMPS.

srnotmonmon'ro mgpart of Letters Patent 1%., erases, dated August e,1895.

Application filed August 7, 1882.-

.To all whom it may concern:

Be it'known that l, THOMAS A. EDISON, of Menlo Park, in the county ofMiddlesex and State of New Jersey, have invented a new and 5 usefulImprovement inlncandescing Conductors for Electric Lamps; and I dohereby declare that the following is a full and exactdescription of thesame.

method and material for forming flexible car-. bon filaments for useasthe'incandescing'con ductors of electric lamps .which will be suitablefor many purposes. This I accomplish by the employment of acarbohydrate, such as pure unstructural cellulose or some compoundthereof, which is formed into filaments and carbonized orfirst'carbonized and then made. into filaments. By some method thecellulose or compound of cellulose is dissolved by a suitable solventand formed intosheets or membranes by allowing it to flow upon platesand there drying it. The filaments with enlarged ends are cut or punchedfrom the sheets or membranes thus formed, which are passed betweensheets of paper or metal for the purpose, and the filaments are thencarbonized by heat understrain and pressure, or the sheets or membranesmay be first carbonized and the filaments'pnnched or cut 7 from thecarbonized sheets' By. another method the cellulose or compound ofcellulose may be dissolved and allowed to harden, in sheets orotherwise, into'a mass more or less solid, and may be then subjectedtoheat and pressure and forced through dies to form ,a. fine filament,which is cut into proper lengths and carbonized by heat under strain andpressure. Before carbonization the enlarged ends may be formed bysoftening the ends -of the filament by a solvent and attaching ieces ofthe softened material thereto, or the seas of. the filament whensoftened may be' doubled upon themselves or otherwise enlarged withoutadding extra material, the

' 5 shortening of the filament being provided for in cdtting;.or thehardened dissolved cellulose or compound of cellulose may be forcedthrough dies under heat and pressure and The object There in view is toproduce 'a Serial No. 68,652. (No speoim ens l formed intofsheets fromwhich the filaments arepu'nched before or after carbonization'.

For the material I may use pure unstructural cellulose, which may bedissolved in cuprammo nic hydrate, or any compound of cellulose may beemployed, such as trinitro cellulose, which may be dissolved or made 5 5plastic by a suitable solvent, such as ethylic acetate, alcohol andether, alcohol and camphor, acetone, nitro-benzol,aniline or glacielacetic acid. Other carbohydrates or nitrates or other compounds thereofcould be treated with proper solvents and used for the purpose. It isevident that a dryingoil, such as dill.- seed-oil, maybe added in any ofthe methods. before described, to increase the flexibility of thefilaments produced, but the use of a. I drying oil I have made thesubject of a sepa' rate applicationfor patent. The carbon filamentsformed inthe manner described of pure unstructurab cellulose or somecompound of cellulose or of other carbohydrates or compounds of thesame, have the properties of flexibility and high resistance when verythin, which are essential in incandescing conductors for electric lamps.

. vWhat I claim is- L/A-fieXiblecarbOn filament for the incandesciugconductor of an electric lamp com posed of carbonized unstrncturalcellulose or other carbo-hydrate or a compound thereof, substantially asset forth. 2. The method of producing. flexible carbon filaments for theineandescingconductors felectric lamps, consisting in carbo hing-nustructural cellulose or other carb hydrate or a compound thereof, thematerial being reduced to-the proper size and shape before 'o'r aftercarbonization, substantially as set forth.

filaments for the iucaudescing conductors of electric lamps, -consistiegin dissolving unstructured cellulose or other carbo-hydrate one.compound thereof, and forming the same into sheets or membranes, and inpunch, 9 5

ing or cutting filaments therefrom before 3.,Th'e method of formingflexible carbon carbonizing the forth.

This specification signed and witnessed this 3d day of June, 1882.

same, srbstantially as set TlIOS. A. EDISON. Witnesses:

RrcHD. N. DYER, EDWARD C. ROWLAND.

